Balance Sheet Components - Summary of Prepaid Expenses and Other Current Assets (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Deferred Costs Capitalized Prepaid And Other Assets Disclosure [Abstract]
Prepaid software and subscription fees	$ 423	$ 376
Prepaid research and development project costs	396	321
Other receivables	297	311
Prepaid insurance	241	991
Other	626	416
Total prepaid expenses and other current assets	$ 1,983	$ 2,415